1. Field of Invention
The present invention is used to transport fluid and is principally useful in collecting samples of fluid from a single patient.
2. Description of the Prior Art
The difficulties inherent in obtaining anything other than a single sample of blood at one sitting from a particular patient have long been recognized and assemblies for such use have been patented. Nugent, U.S. Pat. No. 4,140,108, teaches the use of a sheathed needle mounted on a threaded hub which can be readily adapted to standard blood collection containers. However, Nugent does not teach the use of a flexible, non-cutting cannula which can be used to conveniently draw blood from a catheter prepositioned in the lumen of a blood vessel. Abramson, U.S. Pat. No. 4,166,450, discloses the importance of ensuring that the extraction needle is properly located in the lumen of the blood vessel before atttaching a blood collection container, but discloses the need to either allow a metal needle assembly to remain in place in the vessel or remove that assembly and reinsert a comparable assembly at another insertion site at a later time.
The present state of the medical art requires multiple needle insertions as fluid samples are needed and is at best uncomfortable for the patient who must tolerate multiple needle insertions.
The present invention is particularly advantageous in that it provides a more comfortable, economic and effective way to extract samples of fluid than the prior art while making maximum use of existing sampling and intervenous insertion technology and significantly decreasing discomfort to the patient. In particular, the present invention provides an apparatus and method useful for obtaining one or more fluid samples from a patient from an insertion site into which has been placed a catheter.